Arduino serial communication pc - MAX 232

Good afternoon everyone, I have an Arduino Severino, who has a serial output, with atmel8. I'ma freshman in Arduino and I wonder if the PC to send commands to the arduino I have to use a MAX232 and connect you entries RX and TX arduino or if I can send commands through the serial cable that connects directly to the serial input arduino. If you must use the RX / TX arduino how do I program these inputs to receive data from the PC. Initially I just wanted to make a program to control the turning on and off an LED, and then move to control a motor.

Thanks and await answers.

Yes you can just talk to the arduino from the pc on the built in USB connection. Look up the serial commands in the arduino refance.

Just keep in mind, if you're using the PC serial port to talk to the arduino, it WILL kill the arduino. To elaborate: The serial port on the pc (DB9 connector) uses the standard RS232 voltage levels which are +12v (0) and -12V (1) (Yeah, logic is inverted in reference to voltage levels by the RS232 standard). These voltages will kill the arduino is connected directly. In this case a MAX232 level shifter is required.

As Grumpy_mike noted, if you're just going to talk with the arduino via USB serial link, this link uses TTL levels (+5v and -5V which are NOT the voltage levels specified by the RS232 standard), this will work fine.

In a nutshell: Using serial cable between arduino and PC - need MAX232 Using USB serial link: connect direclty, you're sweet - this link is used to upload programs to the arduino.

HTH -Igor